Trimming fat with fat?

Yet another diet is in the limelight. Fat has risen to the top, protein has stepped down and carbohydrates remain on the outs. This is the focus of a weight loss diet called the ketogenic (or keto) diet. It consists of 70-80 per cent fat, 15-20 per cent protein, 5-10 per cent carbohydrates—a significant shift from Health Canada’s recommendations of 45-65 per cent carbohydrates, 10-35 per cent protein and 20-35 per cent fat.

What is ketosis?

Carbohydrates are broken down in the body into sugar; this sugar partners up with insulin (from the pancreas) to provides fuel to our tissues, muscles and the brain. When there are no carbs/sugars on board, our body taps into fat stores in the liver and converts it to ketones as an alternative energy source. Unlike many diets that focus on low carb/high protein, protein is kept to a moderate level because at high levels it can also trigger insulin, kicking the body out of ketosis. Ketosis usually takes a couple days and ketone levels can be tested through urine dipping strips, blood test or breath test.

Unlike many fad diets out there, the keto diet wasn’t originally developed for weight loss. It dates back to the 1920s for treating epileptic seizures in children. It’s still used today as an effective method in managing seizures when medication options have failed. Most recently it has gained popularity for its role in weight loss, as well as potential benefits in diabetes, heart disease, neurological diseases (Parkinson’s, Alzheimer’s, MS), cancer, thyroid, acne and sleep. Overall, there is a lack of research, especially understanding the ketosis mechanism and long-term effectiveness and safety.

The keto diet does lead to rapid weight loss. Some studies have shown it may be as effective, if not more, as a moderate carb, low-fat diet. Long-term results have not been studied extensively and results are mixed. Some evidence has shown the keto diet has a potential greater initial weight loss in the first six months compared to low-fat diets, but similar total weight loss at a year. Other research has shown the keto diet and a low-fat diet provide similar weight loss but maintenance after one year is better with the keto diet.

There are several hypotheses as to how the diet works. First off, when in ketosis, people tend to experience decreased hunger and satiety, therefore caloric intake decreases. This may be triggered by ketones, changes in hunger hormones and/or the filling impact of protein and fat. Other thoughts have nothing to do with ketosis but an automatic decrease in calories from mindful foods choices and/or cutting out an entire food groups and other high calorie foods like sweets, chips, etc.

Keto diet caveats

Before you replace your bread with buttered bacon, it’s important to talk safety/risks and logistics of actually following the keto diet.

Insulin and carbs play a role in hydration and muscle maintenance/building. When you cut the carbs you also lose water weight (especially initially) and potentially muscle (yes, even with adequate protein intake). Unfortunately, if you fall victim to yo-yo dieting, the re-gain is often put back on as fat. Muscle is only re-built with the hard work of weight training exercises.

In initial days to weeks on the diet, people often experience the ‘keto flu’ which includes increased cravings, irritability, foggy brain, fatigue, headaches and nausea. Luckily, this tends to mellows out and energy and mood improve. Ketone production can result in fruity/acetone smelling breath and urine.

Cutting out or minimizing your intake of food groups increases risk for nutrient deficiency. Fruits and vegetables are a major source of fibre, vitamins and if you’re not obtaining at least five servings a day, you may not be getting enough. A multivitamin may be needed but research shows this is not an equivalent substitution to the disease-fighting properties obtained from the real deal .

Bone density may be negatively impacted by inadequate calcium and vitamin D intake. This has been observed in long-term use for treating epilepsy. Keto sources include canned fish with the bones, margarine (vitamin D), high-fat dairy products and low-carb milk alternatives. Without careful planning or supplements, it’s unlikely you’ll meet your daily needs.

Fibre comes from whole grains, nuts/seeds, vegetable and fruit and it’s nearly impossible to obtain 25g a day without these foods. Diligent planning is required to include higher-fibre foods. Keep in mind that fibre goes beyond regularity, playing a role in controlling blood sugars, cholesterol and potentially decreasing risk of certain cancers.

Excessive saturated fat intake may be linked to elevated cholesterol levels. Saturated fat comes from fatty animal products (processed and red meats, cheese, butter), as well as palm and coconut oil. Unsaturated fats (oil, nuts/seeds, avocado, fatty fish) have been shown to improve cholesterol levels. Most keto studies do not distinguish between types of fat and the impact on heart health remains unconcluded. If you’re following this plan, choose unsaturated fats more often and have your doctor monitor your cholesterol levels. You may want to avoid this diet if you have a history of elevated cholesterol or heart disease.

Carbohydrates help regulate blood sugars. Many studies have shown the keto diet leads to better blood sugar control in type 2 diabetes and improved insulin sensitivity. It’s undetermined if this is due to weight loss, ketosis mechanism and/or decreases in insulin/carb intake.

If you have type 2 diabetes it’s important to talk to your health care professional before following this plan. You may require adjustments to your medication. If you have type 1 diabetes, this diet can be dangerous as it can lead to life threatening elevated ketone levels.

This diet is not recommended for individuals with existing kidney conditions. There is a minimal risk of developing kidney stones on low-carb diets.

Reality check

When it comes to weight loss, there is no ‘one plan fits all’ and the research says the same. As dietitians, we’re keen on plans that promote that fancy term ‘lifestyle’ changes. People are desperately seeking new and rapid methods to lose weight, but often it’s this desperation or glamorizing testimonials that cloud our judgment in sorting out the long-term implications of a plan. Regardless of the approach, we all have moments of falling off track. So take a pause and reflect. Is cutting a major (and often beloved) food group realistic or necessary? Do you have the time for planning, prepping and calculating? You’ll have to stick to the diet in a non-keto world when eating out, social events, workplace—even eating with your family.

Regardless of any plan or change you put in place it’s important to understand your behaviours. Ask yourself why do you eat, what’s your attachment to food, and what makes change hard. Addressing the root of the behaviour and developing alternative coping needs to accompany any plan, otherwise a plan often acts as a temporary bandaid.

At the end of the day the best eating plan is the one you can happily follow. If you hate it, or you’re hungry, or it doesn’t work with your day-to-day life, it’s not the right lifestyle for you.

If you feel keto is for you, speak to a health care professional (family doctor, dietitian, pharmacist) first. You’ll need their guidance to ensure you’re following it in the safest manner possible.